They're huge painted numbers and drawings of tanks bearing the North Korean star emblem.
Through a megaphone, a soldier announces what target to watch. A South Korean F-16 fighter jet screams over shortly after, dropping a bomb right on the spot.
Next up we're treated to the impressive sight of an E-737 "Peace Eye," a state-of-the-art surveillance aircraft that can detect movement across most of North Korea's airspace from behind the South Korean border.
We'd been given rare access to a live-fire exercise involving armed forces from South Korea and the United States.
It happened to coincide with the annual military exercise known as "Ulchi Freedom Guardian," a series of mainly computer-simulated drills involving an estimated 80,000 troops. Its aim is to simulate the defense of South Korea from an attack by the North.
From behind us, the roar of anti-aircraft canon shakes the ground beneath us and leaves us coughing through the thick, acrid smoke. It smells like the end of a major fireworks display on New Year's Eve.
A flight of Surion helicopters, commonly used to transport troops, launches flares designed to evade North Korean surface-to-air missiles.
Commandos then rappel down ropes to the ground -- simulating the infiltration of enemy lines.
"Our soldiers are ready and able," says Battalion Commander Heo Jing-Nyeong, of the South Korean army. "With the will and courage to fight against the enemy."
U.S. Private First Class Israel Corona, part of the American military contingent, tells us, "We're just ready to fight tonight."
North Korean ire
This drill happens every three to five years, with around 3,000 South Korean and American military personnel.
Most joint exercises between the two allies draw an angry response from Pyongyang, who tend to view these events as a provocation and prelude to war.
This year was no different.
In the lead-up to Ulchi Freedom Guardian, the state-run news agency KCNA said North Korea would attack the U.S. mainland
if the drills went ahead year.
Anger over landmines along the DMZ that wounded a South Korean patrol, as well as the placement of loudspeakers
that pumped out South Korean propaganda, has meant that tensions have been especially high recently.
Unperturbed, South Korea still went ahead with UFG and this live fire drill. This was something it wanted its people to see.
Members of the public were even invited along to watch the display -- complete with an army band playing patriotic music. Enthusiastic applause erupted from the crowd every time a bomb hit its target.
The audience was especially impressed by the show of explosions in perfect "V" formations, together with multi-colored smoke billowing from aircraft above.
After the theatrics, there was a chance to inspect the state-of-the-art weapons, as well as photo opportunities with soldiers on hand to explain how everything works.
"I felt really nervous and anxious living in this area," said Pocheon resident, Song Choon-soon. "But after watching the performances I don't feel anxious at all. North Korea can't defeat us."
People here are used to the regular threats from the North. But the South Korean and U.S. militaries took the recent hostilities seriously.
Some residents living close to the line of fire were evacuated, after Pyongyang set a deadline for South Korea to switch off the loudspeakers, promising military action if the broadcasts continued.
For the assembled crowd here, the live fire display seemed to have had the intended effect -- reassuring them that South Korea has the military might to stand up to the threat from its unpredictable neighbor.